Field
Aspects of the present invention generally relate to power management of an image forming apparatus connected to a network.
Description of the Related Art
In Japanese Patent Application Laid-Open No. 2002-297336, as a method for monitoring a state of an image forming apparatus connected to a network, a monitoring terminal acquires state information from the image forming apparatus through periodic polling monitoring.
In Japanese Patent Application Laid-Open No. 2013-9139, as another monitoring method, a monitoring terminal is set so as to issue a Simple Network Management Protocol (SNMP) trap notification tow a monitoring device when a state of a network apparatus has changed, whereby the state of the network apparatus is monitored by the trap notification from the image forming apparatus.
As a method for monitoring a power state of an image forming apparatus, a method for performing device monitoring using an SNMP and a Management Information Base (MIB) is proposed. Particularly, a method for managing the power state of the image forming apparatus from a monitoring terminal using a standard of Printer Working Group (PWG) Imaging System Power MIB v1.0 (hereinafter referred to as Power MIB) (PWG Candidate Standard 5106.5-2011-PWG Imaging System Power MIB v1.0 http://ftp.pwg.org/pub/pwg/candidates/cs-wimspowermib10-20110214-5106.5.pdf) is proposed.
The standard of Power MIB includes, in addition to a method for monitoring by periodic polling from a monitoring terminal, a specification with which a state notification is issued from the side of an image forming apparatus to the side of a monitoring terminal when a power state of the image forming apparatus is shifted.
As a method for actively issuing a state notification using an SNMP/MIB from the side of an image forming apparatus to the side of a monitoring terminal, methods such as SNMPv1-Trap (RFC1157 https://www.ietf.org/rfc/rfc1157.txt), SNMPv2-Trap, and InformRequest are standardized in Request for Comments (RFC).
An SNMP is a User Datagram Protocol (UDP), i.e., a connectionless-type protocol, and does not perform a reach confirmation. Thus, a host application is required, for example, to perform retransmission in a situation of a packet loss and to assure a change of a reach order.
On the other hand, In InformRequest (hereinafter referred to as “inform”), a reach confirmation of a packet is performed. Therefore, as an issue of “inform”, in a case where the power source of an image forming apparatus enters a sleep state, the image forming apparatus returns from the sleep state to a normal state when return of the reach confirmation from a monitoring terminal reaches the image forming apparatus. As another issue, in a case where the power source of the image forming apparatus is turned off, and when the power source of the image forming apparatus is turned off, communication cannot be performed. Therefore, the return of the reach confirmation from the monitoring terminal cannot be confirmed (the reach confirmation cannot be retransmitted even if the return of the reach confirmation has not reached the image forming apparatus).
More specifically, in a case where the state notification of the image forming apparatus has been issued using the notification method in which a reach confirmation is performed, a state of the image forming apparatus is affected due to the return of the reach confirmation from the monitoring terminal and the return of the reach confirmation from the monitoring terminal cannot be confirmed on the side of the image forming apparatus, depending on a state of the image forming apparatus that has been shifted after the state notification.